How to get a value from Kotlin AsyncTask

Question

I can't get one solution for this. I have searched many things and I can't get an answer. Please help me. This is my code

class NewTask : AsyncTask<Void, Void, String>() {
public override fun doInBackground(vararg params: Void?): String? {
    val arr = ArrayList<String>()
    val url = URL("http://boogle.org")

    with(url.openConnection() as HttpURLConnection) {
        requestMethod = "GET"  // optional default is GET

        //arr.add(responseCode)

        inputStream.bufferedReader().use {
            it.lines().forEach { line ->
                //println(line)
                arr.add(line as String)
            }
        }
    }
    return arr.get(0)
}

public override fun onPostExecute(result: String?) {
    //super.onPostExecute(result)

}
}

Does this answer your question? [How to get the result of OnPostExecute() to main activity because AsyncTask is a separate class?](https://stackoverflow.com/questions/12575068/how-to-get-the-result-of-onpostexecute-to-main-activity-because-asynctask-is-a) — mightyWOZ, Jan 11 '20 at 17:31
It answered my question after all but I decided to use coroutines — user6070761, Jan 13 '20 at 19:35

score 1 · Answer 1 · answered Jan 11 '20 at 17:10

1

You can call the get() method of AsyncTask (or the overloaded get(long, TimeUnit)). This method will block until the AsyncTask has completed its work, at which point it will return you the Result.

It would be wise to be doing other work between the creation/start of your async task and calling the get method, otherwise, you aren't utilizing the async task very efficiently.

answered Jan 11 '20 at 17:10

Ravi

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The app freezes when I do get() – user6070761 Jan 11 '20 at 17:54
Update the data at class label and when execution is over PostExecute(), use class-level data which you will update from the background() – Ravi Jan 12 '20 at 07:35
1

I did it via coroutines. – Timotej Leginus Jan 13 '20 at 14:10

score 0 · Accepted Answer · answered Jan 13 '20 at 14:13

I had the same problem, but I settled on coroutines. Here is the code I used:

class CoRoutine{
suspend fun httpGet(url: String = "https://boogle.org): String {
val arr = ArrayList<String>()
withContext(Dispatchers.IO) {
    val url = URL(url)

    with(url.openConnection() as HttpURLConnection) {
        requestMethod = "GET"  // optional default is GET

        //arr.add(responseCode)

        inputStream.bufferedReader().use {
            it.lines().forEach { line ->
                //println(line)
                arr.add(line as String)
            }
        }
    }
}
return arr.get(0)
}
}

Answer taken from my other answer.

How to get a value from Kotlin AsyncTask

2 Answers2